Improvement in malleable-iron castings



Nrrnn STATES' PATENT @Erica ALBERT F. ANDREWS, OF NEW HAVEN, CONNECTICUT, ASISIGNOR TO HIM- `SELF AND HORATIO G. REDFIELD, OF SAME PLACE.

IMPROVEMENT IN MALLEABLE-IRON CASTINGS.

Specication forming part of Letters Patent No. 123,072, dated January 30, 1572; antedated January 20, 1872.

State of Connecticut, have invented certain new and useful Improvements in the Process of Producing Malleablelron Castings, of

y which the following is a specification:

I subject the castings to the influence of hydrogen or its compounds, either alone or associated, or alternated with carbonio oxide or acid at a certain temperature. In one modification of the invention the hydrogen or carbonic oxide or carboniol acid is Vassociated also with lime, oxide of iron, or other metallic bases, either separately or mixed, and in another with clay silicaor the silicates.

The following is a description of what I consider the best means of carrying out the invention. The accompanying drawing forms a part of this specification.

Figui-e l is a vertical sect-ion through a portion of the furnace, showing the cases in position. Fig. 2 is an end view of one of the cases detached. Fig. 3 is a cross-section of the case. Fig. 4 is a longitudinal section through an entire furnace on a smaller scale; and Fig. 5 is a plan View of the arrangement-it is a horizontal section in the plane of the connecting nozzles.

The scale in Figs. l, 2, and 3 is one and a half inches to the foot, and in Figs. 4 and 5 it is one-half an inch to the foot.

Similar letters of reference indicate corresponding parts in all the figures.

The castings are produced in the ordinary manner, from the ordinary varieties or mixtures of iron suitable for this purpose. It will be understood that they are small; but larger sizes of castings may be successfully treated, with proper care, by subjecting the castings for a longer time to the iniiuence of chemicals and heat. The treatment requires a hot furnace, with means for varying the temperature, so that it may be raised toward the latter portion of the treatment of each batch, but which it is intended to keep continuously hot for a long period; a cooling-pit or space, in which the walls may be allowed to remain at a moderate temperature; provisions for manufacturing or supplying hydrogen gas a store of lime and the other materials; and a quantity of adapted to reach into the furnace and to take,

hold of the portable cases, and cranes, overs head railroads, or analogous means for conveniently moving the hot masses from the furnace to the coolingpits.

Referring to the drawing, A A, etc., are the stationary walls of the hot furnace. The inclosed space, it will be understood, is kept at a high temperature by means of a re nnderneath, or at the side, not represented. I have experimented successfully with a iire working like a puddlers iire, or what is called a reverberatory furnace. B B, &c.,are cases, made of fire-clay or other suitable material, of a rectangular form, and provided either with a fixed or with a removable false bottom, B1, below which there is an orifice at each side, one of which is provided with a projecting nozzle, adapted to match into the corresponding hole in the adjacent similar casing. The castings to be treated are packed down in the space above the perforated bottom, with theirregular spaces between lled with inelydivided lime 5 and the top is covered by a luted cap, B2, having a small hole, b, near the center, through which the gas rising through the int-erstices in the lime may escapeA through a. tube, C, which is temporarily attached after the case B and its contents are in position in the fur nace. The tube G may be of small size. lts function is to lead the gas to a convenient point above and outside of the furnace, where the small current'of escaping gas may burn continuously, and indicate to the experienced eye the progress of the work. The hydrogen is supplied from a suitable reservoir, not represented, through the pipe D to one end of the furnace, and maintained at a moderate pressure. It iiows through the vacant space below the false bottoni in each of the cases B, and a portion flows upward through the contents of each case to escape, in a more or less niodiiied condition, at the top. lt usually escapes charged with carbon--in other words,

it escapes as a hydrocarbon. Provision is made in the construction of the cases B for retaining, either within the hole which receives the gas or around the nozzle at the opposite side or end of each case, a ring of properly moistened and plastic clay to serve as a luting. I prefer to apply clay in this manner in both the positions named. IVhen the cases are lowered into their proper positions in the furnace A they are moved endwise successively into the proper position, to thrust the nozzle of one into the hole in the other, and the luting makes an approximately gas-tight joint. It will be understoodfof course, that the termination of the series at each end is properly luted to make a tight connectionwith the walls of the furnace and with the pipe which supplies the gas at one end. I prefer also to connect a pipe to the other end of the furnace, and to cause a current of the gas to flow not only into and along the whole series of cases B, but also to circulate actively quite through the last member of the series and out through the pipe which connects to the corresponding end or side of the furnace. I have found that the effect is about the same if instead of pure hydrogen I use the same largely mixed with carbonic oxide, such as results from the manufacture of hydrogen, by passing steam through a thick bed of red-hot charcoal. I have produced my hydrogen by this means, and operated with it successfully. I can use hydrogen variously otherwise mixed with diluting and neutral agents, but a chemical combination of the hydrogen with any other element which retains it with much tenacity under heat is to be avoided. It is important to present the hydrogen in a free or nearly free condition to allow it to produce the proper action. I h ave experimented successfully with air-slaked lime as the material for packing the castings in 5 but I propose to use lime in other conditions 1n arble-dust, which is carbonate of lime, mingled with large quantities of silica and small quantities of other foreign matter; or, I propose to use peroxide of iron, or finely divided clay, or silicate of aluminium. The main function of the packing material is to afford a support to the castings, to reduce the risk of their becoming much distorted in form at a high temperature under the pressure which they exert on each other, and to allow the access of the hydrogen to and the free escape of the carbon from the castings. I maintain the furnace at a variable, but 'always high temperature, for an indefinite period, lifting ont the cases B and their contents by means of suitable grapples, and carrying them on a crane, or otherwise deposit them in a coolingpit, not represented. The castings remain in the hot kiln or furnace A only a few hours. Sixto ten hours are sufficient for ordinary small castings, as door-latches, gun-locks, and the like. After remaining in the cooling-pit at a moderately high but slowly decreasing temperature for about twenty-four hours, the cases B and their contents may be removed to make way for others, and left to complete their cooling more rapidl yin the open air. The castings produced by my process are of a high quality, and the operation is conducted very rapidly, and with nearly uniform success. Alarge portion of the good effect of my invention may be also realized by submitting the material to the action of the hydrogen, as above described,

only a portion of the time, and in the intervals supplying a stream of other gas to dow through the channels above described. I anticipate a decided advantage from thus alternating the currents of gas under some conditions. I prefer as the alternating gas carbonio acid or carbonic oxide, partly from the superior facility and economy with which. these gases can be produced. I esteem the alternating of the gases one feature of my invention, and it may be carried out without the necessity for drawings or detailed description. It is sufficient to supply any suitable valves to control the induction, and at intervals to shut off the hydrogen, and either stop its manufacture or accumulate a quantity in a suitable holder while the other passage is open, allowing the ow of carbonic oxide or carbonio acid, or of the two mingledin known or unknown proportions, through the spaces in the bottom of each case B, and upward through the interstices in the packing mate-rial, and out through the pipe G, in the same manner las the hydrogen has been represented to iiow. I would name one hour for each as a suitable period. I believe the effect will be more uniform if the operation is conducted by this alternating modification of the invention, although the process may require a little longer time.

I claim- 1. The employment of hydrogen gas in the treatment of malleable-iron castings substantially in the manner and for the purposes herein set forth.

2. I claim in such treatment the employment of hydrogen gas in combination with a packing of lime or metallic oxides, or bases,

or carbonates, or silicates, as herein described.

3. I claim in such treatment the employment of hydrogen. gas, alternating with carbonic oxide or analogous neutral gas, as specified.

In testimony whereof' I have hereunto set my namein presence of two snbscribin g witnesses.

ALBERT F. ANDREWS.

Witnesses:

J. A. RIoHnRDsoN, W. C. HUBBELL. 

